✅ 2023-11-12: Node failure

TODO

Why is everything failing at the same time?

After a full shutdown to turn off power to do electrical work, the Data Node now power cycles about once per second instead of booting. There’s a brief hard drive noise in each cycle, but no beep from the motherboard speaker. The boot loop can be stopped by holding the power button.

Diagnosis

Diagnosed a motherboard failure. Rationale:

• Symptoms began after a full shutdown.
• Symptoms:
  • Fans spin for ~1 second on pushing power button, then stop. Repeats after ~1 second delay, indefinitely.
  • No display
  • No beep from built-in speaker
  • No POST
  • Power cycling stops after holding powr button for 5 seconds.
• Symptoms unchanged when removing all components (one by one): disks, RAM sticks, CPU.
• Symptoms unchanged when replacing (one by one): PSU, PSU cables, wall outlets, CMOS CR2032 battery.
• Symptoms unchanged with multiple PSUs, PSU cables, and wall outlets.

After replacing motherboard, the system resumed functioning.